Help And Shit

Does anyone know how I can make a raster effect to something? I need it to be like dots, with one single color, maybe with varying sizes to give the illusion of light/dark spots. My idiot teacher, who is supposed to know this shit, told me to use the 'Color Halftone' filter. Fuck him.


You get the idea:

External image not preserved — inspect source: http://upload.wikimedia.org/wikipedia/commons/5/5e/CMYK-raster-C.png

I dont have a fucking clue!

Are you trying to do this?
http://www.photoshoplab.com/halftone-mania.html